1. Field of the Disclosure
Embodiments of the present disclosure generally relate to the fields of geology, geophysics, and geomechanics.
2. Description of the Related Art
Reservoir surveillance, using a series of time-lapse seismic snapshots and comparing these to an initial baseline snapshot, can be used to track subterranean rock deformation and fluid flow, leading to better characterization and management of hydrocarbon producing fields. Production and/or injection induced changes in formation pressure, formation stress state, fluid phase saturation, formation temperature, and other relevant parameters are generally known to cause variations in elastic and acoustic impedances and vertical dimensions of reservoir rocks or other formations. These variations in attributes can be monitored by geophysical measurements including 3D Surface Seismic, Vertical Seismic Profile, and Cross Borehole Seismic surveys taken at acceptable intervals while the field is in operation. Changes in seismic measurement attributes including amplitude, phase, impedance and travel-time are qualitatively or quantitatively linked to changes in subterranean parameters such as pressure, stress, saturation, strain, and temperature, and surface parameters such as subsidence. This linkage enables reservoir engineers to trace the deformation of rocks and the movement of produced hydrocarbons and/or injected fluids within the reservoir from seismic measurement attributes. This capability can be used to locate missed hydrocarbon reserves, improve recovery factors, enhance sweep efficiency, streamline operations, predict formation response, and calibrate reservoir simulators.
Two key requirements for interpreting time-lapse reservoir surveillance are reliable estimates of the state of stress & pore pressure and the petrophysical & geomechanical property distribution in the studied subterranean zone. This need for reliability can only currently be met by the use of subterranean compressional and shear interval velocity values, obtained from multicomponent seismic data, while accounting for the effects of lithology and fluid content. However, conventional techniques used for processing noisy multicomponent seismic data are inefficient and typically need an impracticably large storage and processing capacity. An additional important limitation of the state of the art is the inability to resolve small amplitude and hence poor signal-to-noise pulses from low impedance contrast boundaries and/or closely spaced or overlapping reflected seismic pulse arrivals from structural features which can be near the resolution limits of the frequency bandwidth of interrogation.
There is a need, therefore, for a method and/or a system for performing efficient seismic time-lapse characterization of subterranean formations. There is also a need to apply the aforementioned seismic time-lapse characterization to verify and/or calibrate one or more reservoir simulators.